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When do you ovulate on Femara?

Medically reviewed by Carmen Fookes, BPharm. Last updated on July 9, 2020.

Official Answer

by Drugs.com
  • If you are taking Femara for fertility problems, then you usually ovulate four to seven days after taking the last of a five-day cycle of pills.
  • This means that If you started the pills on day three of your period then you should ovulate between days eleven to fourteen.
  • Intercourse or intrauterine insemination should be timed to coincide with ovulation.

Femara (letrozole) is a prescription medication used for the treatment of breast cancer and it is also commonly used off-label to treat ovulation problems including polycystic ovary syndrome (PCOS) and unexplained infertility.

For fertility issues and PCOS, Femara is typically taken once a day for five days. It is usually started on day three or four of your monthly cycle (the first day of your monthly cycle is the first day of your period) and then you ovulate about four to seven days after taking the last of the five pills. This means that if you started the pills on day three of your period then you should ovulate between days eleven to fourteen. Intercourse or intrauterine insemination (the artificial insertion of sperm) should be timed to coincide with ovulation.

How does Femara work for fertility problems?

When you take Femara, it blocks the action of the enzyme aromatase, which prevents the body from converting androgens into estrogens.

In women with fertility problems, blocking the action of aromatase and lowering levels of estrogen causes the body to increase the production of follicle-stimulating hormone (FSH), which stimulates the ovary to produce an egg.

Some women on letrozole will release more than one egg because they produce more FSH while on Femara than a woman produces when ovulating naturally.

References
  • Femara (letrozole) Novartis Pharmaceuticals Corporation https://www.drugs.com/pro/femara.html
  • Legro R, Brzyski R, Diamond M, et al. Letrozole versus Clomiphene for Infertility in the Polycystic Ovary Syndrome. N Engl J Med 2014; 371:119-129 DOI: 10.1056/NEJMoa1313517
  • Franik S, Eltrop SM, Kremer JA, Kiesel L, Farquhar C. Aromatase inhibitors (letrozole) for subfertile women with polycystic ovary syndrome. Cochrane Database Syst Rev. 2018;5(5): CD010287. Published 2018 May 24. DOI:10.1002/14651858.CD010287.pub3

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